Help assigning subsequent invoice numbers

Hi katyaking10 

If you want to add the sebsequent invoice number, you need to have a unique column to rank it, but on the sample data you have offered, you don't have the unqiue column, so it is better that, add an index column in power query first, select from 1, then apply it to power bi desktop.

Then create a calculated column, you can refer to the following code.

Final_No =
VAR a =
    INT (
        RIGHT (
            [Last No Used],
            LEN ( [Last No Used] ) - SEARCH ( ".", [Last No Used], 4 )
        )
    )
VAR b = a + [Index]
RETURN
    LEFT ( [Last No Used], LEN ( [Last No Used] ) - LEN ( b ) ) & b

Output

Best Regards!

Yolo Zhu

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